France and Britain are pressing ahead with plans for a multinational naval mission to safeguard shipping through the Strait of Hormuz, assuming a U.S.-Iran ceasefire takes hold, but Iranian officials are already signaling strong opposition.

"Iran is hostile to any foreign military presence but open to dialogue," a European official said Tuesday.

An Iranian security official was less diplomatic, saying, "Any presence of foreign countries, whether to safeguard shipping or clear mines, is unacceptable."

French Foreign Minister Jean-Noel Barrot told reporters the European-led mission is "already ready" after weeks of planning among roughly a dozen militaries.

"France, the United Kingdom, and several dozen countries have put together a strictly defensive international mission, independent from the parties to the conflict, capable of deploying rapidly to ensure freedom of navigation," Barrot said.

The effort is expected to be discussed by G7 leaders as they consider how to secure the waterway, which normally carries about one-fifth of global oil and liquefied natural gas supplies.

President Donald Trump has repeatedly predicted the strait will reopen quickly, telling reporters Monday, "Ships are starting to go out now. On Friday, it'll be completely opened."

But European leaders and some U.S. officials are questioning such an aggressive timeline.

One senior U.S. official said shipping traffic would increase gradually and could take up to two weeks to recover significantly, with mine-clearing and security concerns still unresolved.

French President Emmanuel Macron said a naval mission could be deployed "in two to three days" if all parties agree.

Regardless of the specifics, European governments are proceeding cautiously.

Spanish Foreign Minister Jose Manuel Albares said, "We're in a very incipient phase. Let's not get ahead of ourselves."

At the same time, Iran remains adamantly opposed to outside involvement.

A second Iranian security official said Tehran has "zero trust in foreign countries" and insisted responsibility for the strait rests with Iran and Oman.

Analysts warn that even if a ceasefire holds, restoring confidence among shippers and insurers could take months.

As MIT professor Caitlin Talmadge told Reuters this week, mine-clearance operations require "a permissive environment," and vessels conducting them "could be vulnerable if Iranian attacks resume."